[Core] Add GetIsLastVariant for UI

3 files changed, 64 insertions, 7 deletions

diff --git a/Xamarin.PropertyEditing/ViewModels/PanelViewModel.cs b/Xamarin.PropertyEditing/ViewModels/PanelViewModel.cs
index 1d9e7a1..7b41e74 100644
--- a/Xamarin.PropertyEditing/ViewModels/PanelViewModel.cs
+++ b/Xamarin.PropertyEditing/ViewModels/PanelViewModel.cs
@@ -57,7 +57,7 @@ namespace Xamarin.PropertyEditing.ViewModels
 			if (editor == null)
 				throw new ArgumentNullException (nameof(editor));
 
-			var list = GetList (editor);
+			var list = GetListCore (editor);
 			if (editor is PropertyViewModel pvm && this.targetPlatform.GroupedTypes != null && this.targetPlatform.GroupedTypes.TryGetValue (pvm.Property.Type, out string groupName)) {
 				var group = list.OfType<PropertyGroupViewModel> ().FirstOrDefault (gvm => gvm.Category == groupName);
 				if (group != null) {
@@ -99,6 +99,14 @@ namespace Xamarin.PropertyEditing.ViewModels
 			this.isExpanded[mode] = expanded;
 		}
 
+		public IReadOnlyList<EditorViewModel> GetList (EditorViewModel evm)
+		{
+			if (evm == null)
+				throw new ArgumentNullException (nameof(evm));
+
+			return (IReadOnlyList<EditorViewModel>)GetListCore (evm);
+		}
+
 		private Dictionary<PropertyArrangeMode, bool> isExpanded;
 		private readonly ObservableCollectionEx<EditorViewModel> editors = new ObservableCollectionEx<EditorViewModel> ();
 		private readonly ObservableCollectionEx<EditorViewModel> uncommonEditors = new ObservableCollectionEx<EditorViewModel> ();
@@ -119,7 +127,7 @@ namespace Xamarin.PropertyEditing.ViewModels
 			if (editor == null)
 				throw new ArgumentNullException (nameof (editor));
 
-			var list = GetList (editor);
+			var list = GetListCore (editor);
 			if (editor is PropertyViewModel pvm && this.targetPlatform.GroupedTypes != null && this.targetPlatform.GroupedTypes.TryGetValue (pvm.Property.Type, out string groupName)) {
 				var group = list.OfType<PropertyGroupViewModel> ().FirstOrDefault (gvm => gvm.Category == groupName);
 				if (group != null)
@@ -133,7 +141,7 @@ namespace Xamarin.PropertyEditing.ViewModels
 			OnPropertyChanged (nameof(HasUncommonElements));
 		}
 
-		private IList<EditorViewModel> GetList (EditorViewModel evm)
+		private IList<EditorViewModel> GetListCore (EditorViewModel evm)
 		{
 			if (this.separateUncommon && evm is PropertyViewModel pvm)
 				return pvm.Property.IsUncommon ? this.uncommonEditors : this.editors;
@@ -341,6 +349,30 @@ namespace Xamarin.PropertyEditing.ViewModels
 			ArrangedPropertiesChanged?.Invoke (this, EventArgs.Empty);
 		}
 
+		internal override bool GetIsLastVariant (PropertyViewModel viewModel)
+		{
+			if (viewModel == null)
+				throw new ArgumentNullException (nameof (viewModel));
+			if (!viewModel.IsVariant)
+				throw new ArgumentException ($"{nameof (viewModel)} is not a variant", nameof (viewModel));
+
+			string groupKey = GetGroup (viewModel);
+			PanelGroupViewModel group = this.arranged[groupKey];
+
+			var list = group.GetList (viewModel);
+
+			int index = list.IndexOf (viewModel);
+			if (index == -1)
+				throw new KeyNotFoundException ($"{nameof (viewModel)} was not found");
+
+			if (++index == list.Count)
+				return true;
+			if (list[index] is PropertyViewModel pvm) {
+				return !Equals (viewModel.Property, pvm.Property);
+			} else
+				return false;
+		}
+
 		private readonly OrderedDictionary<string, PanelGroupViewModel> arranged = new OrderedDictionary<string, PanelGroupViewModel> ();
 
 		private PropertyArrangeMode arrangeMode;
diff --git a/Xamarin.PropertyEditing/ViewModels/PropertiesViewModel.cs b/Xamarin.PropertyEditing/ViewModels/PropertiesViewModel.cs
index 1c694d8..bc8e2e0 100644
--- a/Xamarin.PropertyEditing/ViewModels/PropertiesViewModel.cs
+++ b/Xamarin.PropertyEditing/ViewModels/PropertiesViewModel.cs
@@ -216,6 +216,14 @@ namespace Xamarin.PropertyEditing.ViewModels
 		{
 		}
 
+		/// <summary>
+		/// Gets whether the <paramref name="viewModel"/> is the last-arranged variant property of its base property
+		/// </summary>
+		internal virtual bool GetIsLastVariant (PropertyViewModel viewModel)
+		{
+			throw new NotSupportedException();
+		}
+
 		private INameableObject nameable;
 		private bool nameReadOnly;
 		private bool eventsEnabled;
@@ -581,10 +589,10 @@ namespace Xamarin.PropertyEditing.ViewModels
 			if (baseVm.HasVariations) {
 				using (await AsyncWork.RequestAsyncWork (this)) {
 					var variants = await GetVariationsAsync (property);
-					baseVm.HasVariantChildren = variants.Count > 0;
-
-					foreach (PropertyVariation variant in variants) {
-						vms.Add (CreateViewModel (property, variant));
+					if (baseVm.HasVariantChildren = variants.Count > 0) {
+						foreach (PropertyVariation variant in variants) {
+							vms.Add (CreateViewModel (property, variant));
+						}
 					}
 				}
 			}
@@ -610,6 +618,7 @@ namespace Xamarin.PropertyEditing.ViewModels
 			else
 				vm = new StringPropertyViewModel (TargetPlatform, property, this.objEditors, variant);
 
+			vm.Parent = this;
 			vm.VariantsChanged += OnVariantsChanged;
 			return vm;
 		}
diff --git a/Xamarin.PropertyEditing/ViewModels/PropertyViewModel.cs b/Xamarin.PropertyEditing/ViewModels/PropertyViewModel.cs
index 7d9067f..593aa51 100644
--- a/Xamarin.PropertyEditing/ViewModels/PropertyViewModel.cs
+++ b/Xamarin.PropertyEditing/ViewModels/PropertyViewModel.cs
@@ -636,6 +636,12 @@ namespace Xamarin.PropertyEditing.ViewModels
 
 		public bool IsVariant => Variation != null;
 
+		public PropertiesViewModel Parent
+		{
+			get;
+			internal set;
+		}
+
 		public abstract Resource Resource
 		{
 			get;
@@ -724,6 +730,16 @@ namespace Xamarin.PropertyEditing.ViewModels
 			get;
 		}
 
+		public bool GetIsLastVariant ()
+		{
+			if (Variation == null)
+				return false;
+			if (Parent == null)
+				throw new InvalidOperationException ($"{nameof(Parent)} must be set in order to determine last variant");
+
+			return Parent.GetIsLastVariant (this);
+		}
+
 		public override int CompareTo (EditorViewModel other)
 		{
 			int compare = base.CompareTo (other);